Cocos2d-x 3.0 development notes --- use of vector

Recently I learned from other people's source code and came into contact with the Vector Template Class. I found it very useful. Let's record it and study it.

Let's take a look at the usage: <喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> VcD4KPHA + PC9wPgo8cHJlIGNsYXNzPQ = "brush: java;"> std: vector V;Std is the namespace

T indicates the object type. It can be an integer int, a string, a structure struct, or a custom class;

In my understanding, the program dynamically manages the memory by extending the array.

For details, click the open link (Wikipedia)

Write the following code:

If I need an object, it has four attributes, and I need to read data from the xml file, assign them to the object, add them to the array, and perform unified operations on them.

You can also use the class + array method, but it is not efficient.

Let's see how struct + vector is implemented:

. H

struct config{string name;string id;string price;string description;}

vector
 
   item_config;
 

. Cpp

Config item; item. name = "bomb"; item. id = "0"; item. price = "100"; item. description = "Earth bomb, powerful but cheap"; item_config.push_back (item); // Add it to victor char name = item_config [0]. name; // obtain

Is it convenient? If the array + class code is used, it goes up and no new is required.->

• Access Element Method
  • vec[i]-Element reference with an access index value of I. (The index value starts from zero, so the first element is vec [0].)
  • vec.at(i)-When an element with an access index of I is referenced, array boundary check is performed for at () access. If the access is out of bounds, an exception is thrown, which is the only difference from operator.
  • vec.front()-Return the reference of the first element of the vector.
  • vec.back()-Return the reference of the final element of the vector.
  • Method for adding or removing elements
    • vec.push_back()-Add elements to the tail end of the vector and configure the memory if necessary.
    • vec.pop_back()-Delete the element at the end of a vector.
    • vec.insert()-Insert one or more elements to any position in the vector.
    • vec.erase()-Delete one or more elements in a vector.
    • vec.clear()-Clear all elements.
    • Get length/Capacity
      • vec.size()-Obtain the number of elements currently held by the vector.
      • vec.empty()-If the vector is empty, true is returned.
      • vec.capacity()-Obtain the maximum number of elements that a vector can currently accommodate. This method is related to the memory configuration. It usually only increases and does not decrease because the elements are deleted.
      • Reconfigure/Reset Length
        • vec.reserve()-If necessary, you can change the vector capacity (configure more memory ). In many practical STL jobs, the capacity can only be increased and cannot be reduced.
        • vec.resize()-Changes the number of elements currently held by a vector.
        • Iteration (Iterator)
          • vec.begin()-Return an Iterator pointing to the first element of the vector.
          • vec.end()-Return an Iterator pointing to the next position of the element at the end of the vector (Note: it is not the last element ).
          • vec.rbegin()-Return a reverse Iterator pointing to the final element of the vector.
          • vec.rend()-Return an Iterator pointing to the first element of the vector.